Heavy rolling equipment is used in construction industries and in the underground mining industries. Substantial time, expense, and loss of production can result from punctured pneumatic tires used on such equipment. In some instances, standard pneumatic tires have been filled with fluid rubber, elastomeric or urethane foam materials which solidify in the tire to avoid flats and down time associated with repairing and reinflating the tires. This has not been found to be totally satisfactory because the standard pneumatic tires have a very large capacity for such elastomeric foam or solidifying rubber, so that the weight of such tires is substantially increased. Also, it has been found that such foam-filled tires nevertheless deteriorate quickly under heavy loading conditions, which results in breakage and cracking of the foam and chunking of the tire tread. The increased weight inside of the tires increases the wear and tear on both the tire and the equipment.
Solid rubber tires have been used in lighter vehicles in the past and considerable effort has been expended in attempting to avoid slippage of such solid rubber tires on the wheel rims. For example, a solid rubber tire disclosed in U.S. Pat. No. 1,301,230 issued to Cooper, has layers of rubber belts mechanically secured one layer to the next through brads and to the rim through radially extending spring-loaded bolts having enlarged heads to hold the multiple layers inward toward the rim. The bolts also tend to reduce circumferential slippage with respect to the rim. The bolts can result in uneven support pressure in the tire so that bumping will occur on a heavy loaded tire.
U.S. Pat. No. 2,882,950 issued to Grove, discloses a solid rubber tire for use with heavy rolling equipment around mines, construction jobs, and lumber camps. Reinforcing U-bolts are formed into solid rubber tires radially spaced and extending laterally across the tire just below the exterior surface and down each side where the bolts are secured to upwardly projecting side rim portions. These bolts also result in an uneven load carrying capabilities as it rolls from bolt, to rubber, to bolt repeatedly.
More recent improvements in the construction of wheels and tire assemblies with solid rubber tire for use on heavy construction equipment have been disclosed in U.S. Pat. Nos. 4,966,212 and 5,053,095 issued to Hill. These patents disclose a wheel and tire assembly which provides a large metal cylinder having side rims extending therearound and welded cross bars evenly spaced around the circumference of the rim surface and extending laterally between the side rim portions. These wheel and solid rubber tire assemblies provide substantial advantages over previously existing solid rubber tires. The cross bars are well below the tire surface to reduce the bumping effect of the lateral cross bars. However, although the type of bumping and uneven rolling which was associated with the U-bolts of Grove was substantially reduced while maintaining durability, it has been found that under extreme high pressure loading of low profile solid tires, such as that found in underground mining equipment, a certain amount of unevenness of the tire support occurs and some bumping results. Further, the in constructions where rectangular cross bars are used, such bars may present disposed sharp corners along a relatively short lateral top edge against which the rubber is compressed under heavy loading.
In each instance above, the increased pressure at the support bolts or bars, also accelerates tire deterioration. Further, previous solid tires relied upon side rim portions extending upward from the wheel rim to reduce side-to-side or axial slippage of the tires. Bonding of the tire directly to the rim was not always an adequate solution to axial slippage.